From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [patch] PCI: disable MSI on more ATI NorthBridges Date: Fri, 19 Oct 2007 16:21:18 -0400 Message-ID: <471911BE.2000405@garzik.org> References: <20071019195749.GK29903@austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:38260 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759478AbXJSUVa (ORCPT ); Fri, 19 Oct 2007 16:21:30 -0400 In-Reply-To: <20071019195749.GK29903@austin.ibm.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Linas Vepstas Cc: Shane Huang , davem@davemloft.net, gregkh@suse.de, htejun@gmail.com, brice.goglin@gmail.com, david.gaarenstroom@gmail.com, linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, shane.huang@amd.com, linux-ide@vger.kernel.org, Brice Goglin Linas Vepstas wrote: > On Fri, Oct 19, 2007 at 09:17:23PM +0800, Shane Huang wrote: >> Since we have little experience on PCI and MSI here, we had to try to > > As someone else pointed out, AMD should have *lots* of people with > pci and msi experience on the payroll. (Folks here buy AMD-designed > pci chips ...) > >> ONLY >> comment out the pci_intx() call in drivers/ata/ahci.c >> My system can boot up too with MSI enabled! >> >> So does it mean that the root cause is our SB700 SATA controller >> has a hardware bug where setting INTX_DISABLE in the PCI COMMAND >> register masks MSI interrupts too? > > That's what it sounds like, to me. > >> And what is the software solution or workaround? > > Not sure. Sounds like the device driver needs a quirk for this part. Take a look at tg3.c net driver change 2fbe43f6f631dd7ce19fb1499d6164a5bdb34568 which is a similar situation. However, it may turn out that removing the pci_intx() stuff as a general rule is easier than quirking these devices, if enough of them turn out to have this hardware bug. The tg3.c change should illustrate how to fix immediately, though. Jeff